Potato mop-top virus
What is potato mop-top virus (PMTV)?
Potato mop-top virus (also known as PMTV or Pomovirus solani) is a plant virus that affects potato. The virus causes spraing disease, which is characterised by brown, arc-shaped or ring-like markings inside potato tubers. This can lead to a loss in quality and market value of potatoes.
Signs of PMTV
Symptoms of PMTV in potato tubers include:
- brown arcs or rings in tuber flesh
- distortions to the skin of tubers
- rotting of tuber flesh.
Symptoms of PMTV in plants include:
- mottled leaves (pattern of irregular marks, spots, streaks)
- leaf vein clearing (leaf veins becoming translucent or yellow)
- leaf distortion
- stunted growth.
For photos of PMTV symptoms, please check the photo sections of the European and Mediterranean Plant Protection Organization web page.
How is it spread?
PMTV is primarily spread by the soilborne fungus, Spongospora subterranea, which causes powdery scab of potatoes and is widespread across potato-growing regions in Australia. PMTV survives for more than 10 years in the resting spores of S. subterranea in the absence of host plants. Soil and any material that is contaminated with soil infected with S. subterranea (e.g. equipment, tools or bulbs) can spread PMTV.
PMTV can also be spread by infected planting material (such as seed potatoes). Because of this, it is recommended that you do not compost potatoes at home and use only certified seed potatoes that have been tested for PMTV for planting.
Prohibitions, restrictions and conditions
The entry or importation of host material is detailed in the ‘Order prohibiting or restricting the entry or importation into Victoria of materials which are hosts of Potato Mop-Top Virus’ (GG2025G036.pdf). The order prohibits the entry into Victoria of any of the following host material:
- Seed potatoes
- Potato plants
- Potatoes intended for ware or processing (exemption available if certain conditions are met – refer to Plant Quarantine Manual link below)
- Soil and agricultural equipment
- Plants in tissue culture
This prohibition excludes processed potato products.
Inspections on arrival may be requested, and consignments must meet all requirements.
For entry requirements into Victoria please visit the Plant Quarantine Manual
Applying for a permit
If you wish to import host material that does not meet the exemptions detailed in the order, you will need to apply for and be issued a permit from Agriculture Victoria. Permits will be considered on a case-by-case basis where the risk can be managed. To apply for a permit, visit the Plant biosecurity permit page or contact market.access@agriculture.vic.gov.au
What you can do
If you suspect PMTV may be present on your property, you must notify Agriculture Victoria by:
- using the online reporting form at www.agriculture.vic.gov.au/reportpestsonline
- calling the Exotic Plant Pest Hotline at 1800 084 881
When reporting suspect pests, good photos are helpful. For a guide on taking good pest images, please visit www.agriculture.vic.gov.au/takeaphoto
Growers are reminded that it is an offence under the Plant Biosecurity Act 2010 not to report a suspected case of PMTV.
Reporting an unusual plant insect pest or disease
Report any unusual plant pest or disease immediately using our online reporting form or by calling the Exotic Plant Pest Hotline on 1800 084 881. Early reporting increases the chance of effective control and eradication.
Please take multiple good quality photos of the pests or damage to include in your report where possible, as this is essential for rapid pest and disease diagnosis and response.
Your report will be responded to by an experienced staff member, who may seek more information about the detection and explain next steps.
Report online